@György-Farkas I was hoping to use a single power supply for this project, I'm using the arduino for a few analog sensors, the omega runs the main logic for everything and offer a server to manage the solution, I also want to power a few 12V motors hence why I'm using a 12v 2amp power supply. I am in fact using a heatsink in both regulators with a bit of thermal paste on them

a heatsink like this one

if I supply 5v to the 3.3v regulator them the one that gets super hot 70+ centigrade is the 5v regulator (both regulator I have with a heatsink.)

@ccs-hello I am in fact using the capacitor as specified by the datasheet.

hmm still think I'm doing something wrong somewhere, with the led everything is fine, but as soon as I powerup the omega2, the regulator starts getting super hot, using a kitchen probe it reached 70 degrees C in about 5 mins and it kept rising.

for this I'm using an L7805 to power the arduino from 12v and a MIC29300 to power the onion omega2 from 12v. the problem I'm having is that for some reason the out of the MIC29300 is the same as the input voltage, so if I hook it to 12v the out is 12 and is I connect to 5v the output is 5V. I am not sure at all what I'm doing wrong here.